1. CYTOGENETIC AND BIOLOGICAL STUDIES I.1 Plasmacytomagenesis a) Characterization of the MPC-precursor cell. b) Continued studies on the MPC-accelerating role of A-MuLV. c) The genetics of MPC susceptibility at the target cell level. I.2 Tumor suppression a) Murine system: Analysis of individual chr mediated suppressor effects. b) Human system: Suppression of clonability and tumorigenicity in human BL cells. II. MOLECULAR STUDIES II.1 Functional studies on myc a) Continued studies on the effect of c-myc on SV40 replication: i) Definition of c-myc domains involved in the stimulation of SV40 replication; ii) Identification of protein(s) that interact with c-myc in this system. b) SV40-Rb-myc interactions: i) Can c-myc interfere with the negative effect of Rb on SV40 replication? ii) Is the growth suppression by the Rb gene product abrogated by constitutive c-myc expression? II.2 Continued studies on a myc associated protein kinase activity. II.3 Continued studies on the Ig/myc translocations: Molecular analysis of the new 15;16 and the 6;12 translocations in MPC; Analysis of myc transcription in RICs and MPCs with distant breakpoints. II.4 Continued studies on B-myc: Effect on the SV40 system; differentiation-related studies. III. AUXILIARY STUDIES: Are Rb or p53 changed in Ig-myc translocation-carrying tumors?